how to have one force field influence on 2 collection?
The basic way to affect a force field to an emitter: Put your force field into a collection (let's call the collection Force), select your emitter and in the Properties panel &gt; Particle &gt; Field Weights &gt; Effector Collection, choose the collection called Force. Do the same for the other emitters. It seems a bit buggy so if it doesn't work, remove the Effector Collection and select it again (or tweak some values in the particle settings).
If the emitter has no Effector Collection, all the force fields of the 3D scene will affect it.
If your 2 emitters have 2 different effector collections and you want to affect one force field to both these 2 objects, then put your force field into both these 2 collections (ShiftM &gt; Link to Collection).